From German Specification laid open to inspection No. 2,407,269 such a tool is known in which a coiled spring lies in the receiver between the two cutter members and thereby presses them outwardly. This construction however has the disadvantage that the spring force and thus the cutting force of the cutting members is dependent on the diameter of the respective bore to be deburred. This rests on the fact that with smaller bores the cutting members are pressed inwards so that in the working state the spring force is greater than with larger bores in which the cutter members are located further outwards.
A further problem in the deburring of passage bores consists in that the tool has to overcome a comparatively great cutting resistance if the tool is to remove the first burr of the bore. It would be ideal if the deburring tool upon removal of the first burr in the bore has a comparatively large constant spring force, that is, is practically rigid and which following thereon springs softly into the bore so that an actual de-burring also takes place on both sides in the passage bores. This problem is also not solved with the known tool above described.
The object of the invention is therefore to cushion the cutting members such that at the beginning of the entry into the bore and at the outlet they are practically rigid, that is, are only slightly cushioned in order to remove the first and last burr and the sharp edge of the passage bore with certainty and when the cutting members then enter the bore to provide very soft and uniformly cushioned spring force, independently of whether the passage bore has a large or small diameter.
As distinguished from from a tool of the type mentioned above the instant tool is successful according to the invention in that the spring operates as of a sprung crank slide.
Due to these features the bore is de-burred and smoothed to a very high quality. After overrunning the locking given by the spring constant binding, the cutter members need no longer be adjusted for the specified work area. The cutter members are during the deburring in the position in which they were ground which ensures that there is no profile distorsion and good results.
A practical example with which the desired suspension of the cutting members is obtained is characterised in that a torsion spring is on the one hand fixed firmly to the housing and on the other hand engages in an intermediate member rotatable in a bore, which intermediate member engages with projections free of play in recesses in the cutting members.
Independently of the angle which is formed between the projections and the path of displacement of the cutting members in their slots a crank-slide-like suspension characteristic is obtained. In addition both cutter members can be adjusted together because one and the same spring causes the engagement of both cutter members through the intermediate members.
For the setting of the adjusting path of the cutter members to different diameters it is preferred to provide an adjusting screw actuated by means of outside contacts or tools, the tip of which contacts the face of the intermediate member. Thus also the path of adjustment in both cutter members is adjusted at the same time through one and the same adjusting screw.
The exchanging of the two cutter members is made particularly simple by providing one screw with an eccentric projection which engages in recess in the intermediate member. By a rotation of the screw, in one direction, the intermediate member is pushed into its bore in an axial direction so that extensions on the intermediate member are brought into engagement with recesses in the cutter members and rotating of the screw in the other direction causes the extensions to come out of the recesses for removal of the cutter members. By a simple rotation of this screw therefore an exchanging of the cutter members is possible.